6,7,12,13 - tetrahydro - 6,12 - imino - 5h - benzo(5,6)cyclooct(1,2 - b)indole derivatives and process for their production



United States Patent Office 3,518,270 Patented June 30, 1970 US. Cl. 260286 9 Claims ABSTRACT OF THE DISCLOSURE The invention describes compounds of structure I and a method for their production. They are prepared by cyclization of compounds of structure 11 N-Rz I CH2 3 R4 N H (II) by treatment with excess dilute acid. Compounds of structure I, wherein R is H, can be alkylated. Compounds of structure I, wherein R is benzyl, can be debenzylated. Compounds of structure I are useful as central nervous system stimulants, central nervous system depressants and useful as antifungal agents.

This application is a continuation-in-part of our copending application Ser. No. 634,133, filed Apr. 27, 1967.

The present invention relates to 6,7,12,13-tetrahydro- 6,12-imino 5H benzo[5,6]cyclooct[1,2-b1indole derivatives as well as to a process for the production of these indole derivatives.

The indole derivatives of this invention may be represented by the formula:

owe:

wherein R is hydrogen, lower alkyl or aralkyl; R is hydrogen, lower alkyl, or aralkyl; R is hydrogen or lower alkoxy; and R is hydrogen or lower alkoxy.

In the above definition lower alkyl and the alkyl portion of lower alkoxy or the alkyl portion of aralkyl contains from 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and the like. The aryl portion of aralkyl includes both monohomocyclic ring systems such as phenyl as well as monoheterocyclic ring systems such as furyl, pyridyl, and the like.

This invention also includes within its scope acid addition salts of the subject compounds as Well as various dosage forms containing the same.

The compounds of this invention in which R is H and R is lower alkoxy are useful as central nervous system stimulants in a mammalian host. They are administered at a dosage level of to 500 mg. several times daily, orally or by injection, to produce the desired stimulant effect. Compounds in which both R and R are lower alkoxy are useful as central nervous system depressants. A dose level of 100 to 500 mg. several times daily produces the desired depressant effect.

In addition, the compound in which R =CH R -H, R =H, R =methoxy, has been found to be useful in inhibiting the growth of fungi such as T. mentagrophytes, Aspergillus niger, and C. neoformans in the presence of serum at concentration of 60 to mg./ml. To use it as an antifungal agent, it is combined with an inert carrier such as talc and apply as a 1% to 10% dusting powder.

According to the novel process of this invention, the above compounds may be prepared by treating a l-indolylmethyl-l,2-dihydroisoquinoline of the formula:

R3 [R4 N H (II) with an excess of a dilute aqueous acid at about 90 to 98 C.

The preparation of the starting compound II is fully described in our copending application Ser. No. 634,133 filed Apr. 27, 1967, and entitled 3-Indolylmethyl-3,4- Dihydroisoquinoline Derivatives and Process for Their Production.

The foregoing reaction may be illustrated by the following scheme:

wherein R is hydrogen, R is alkyl or aralkyl.

In order to obtain those compounds of the invention wherein R is alkyl or aralkyl, compounds in which R is hydrogen are treated with an appropriate alkyl halide such as methyl iodide, ethyl bromide, or an aralkyl halide such as benzyl bromide and the like in the presence of a base such as sodium amide in liquid ammonia.

In order to obtain those compounds in which R is hydrogen, the compounds of this invention wherein R is aralkyl are hydrogenated in the presence of a suitable catalyst. Thus, for example, the hydrogenation may be effected by treating the starting compound with gaseous hydrogen under pressure in the presence of palladium on carbon.

The compounds of this invention form acid addition salts. Such salts are readily prepared by the usual methods, such as, for example, the reaction of a stoichiometrically equivalent amount of the base and the desired acid in an inert common solvent. Examples of acids which are suitable for the preparation of acid addition salts of the amine base of this invention are inorganic acids, such as, for example, hydrochloric, nitric, sulfuric, phosphoric, and the like acids, and organic acids, such as, for example, benzoic, acetic, salicyclic, maleic, tartaric, citric and the like acids. The preferred salts are those which are pharmaceutically acceptable, that is, they are acid addition salts which are no more toxic than the bases from which they are prepared and which possess the necessary physical properties that render them suitable for incorporation into dosage forms in combination with the desired pharmaceutical carriers.

The following examples are included in order further to illustrate the invention. All temperatures are given in degrees centigrade. Room temperature is about 20 C. to 30 C.

EXAMPLE 1 EXAMPLE 1 6,7,12,l3-tetrahydro-9-methoxy-14-methyl-6,12-imino- H-benzo [5 ,6] cyclooct[ 1,2-b indole Amixture of 173 g. (0.4 mole) of 1-(indol-3-ylmethy)- 6-methoxy isoquinoline methiodide, 30.3 g. (0.8 mole) of lithium aluminum hydride, and 4000 ml. of tetrahydrofuran is stirred overnight at room temperature. The reaction mixture is hydrolyzed and filtered. To the filtrate is added 2730 ml. of 1 N hydrochloric acid and the tetrahydrofuran is distilled off. After the addition of 1500 m1. of methanol and 1360 ml. more in hydrochloric acid, the mixture is refluxed for 1 hour and the methanol is removed by distillation. The resulting aqueous solution is made basic with ammonium hydroxide and extracted with dichloromethane. Concentration of the dried dichloromethane solution gives a total of 93 g. of 6,7,12,13- tetrahydro-9-methoxy-14-methyl-6,12-imino 5H benzo [5,6]cyclooct[1,2-b]indole as a crystalline product (combination of 3 crops), M.P. 269-270 dec. Recrystallization from methanol-dichloromethane gives material,M.P. 271- 272 dec.

Analysis.-For C H N O. Calcd (percent): C, 78.92; H, 6.62; N, 9.20. Found (percent) C, 78.86; H, 6.66; N, 9.01.

The phosphate salt, recrystallized from water has M.P. 195-205 dec.

Analysis.For C H N O.H PO /2H O (percent) Calcd: C, 58.39; H, 5.88; N, 6.81; P, 7.53. Found (percent): C, 58.64; H, 5.99; N, 6.64; P, 7.43.

EXAMPLE. 2

6,7, 12, 1 3-tetrahydro-9-methoxy-l4-benzyl-6, IZ-imino- SH-benzo [5 ,6] cyclooct[ 1,2-b] indole A mixture of 9.6 g. (0.021 mole) of 1-(indol-3-ylmethyl)-6-methoxy-isoquinoline benzyl bromide salt, 2.5 g. of lithium aluminum hydride and 210 ml. of tetrahydrofuran is stirred at room temperature for 18 hours.

The reaction mixture is hydrolyzed in the usual manner and filtered. To the filtrate is added 205 ml. of 1 N hydrochloric acid and the tetrahydrofuran is distilled all. After the addition of 300 ml. of methanol and 103 ml. more 1 N hydrochloric acid, the mixture is refluxed for 1 hour and the methanol is removed by distillation. The resulting aqueous solution is made basic with ammonium hydroxide and extracted with dichloromethane. The residue from evaporation of the dried dichloromethane solution is triturated with methanol to give 6.8 g. of 6,7,12,13-tetrahydro-9-methoxy-14-benzyl 6,12 imino-5H-benzo[5,6] cyclooct[l,2-b]indole as a crystalline product, M.P. 230- 232 dec. Recrystallization from methanol-dichloromethane gives material, M.P. 231.5-232.5 dec.

Analysis.For C H N O. Calcd. (percent): C, 82.07; H, 6.36; N, 7.36. Found (percent): C, 81.93; H, 6.38; N, 7.22.

EXAMPLE 3 OCHa 1 NH 6,7,12,13-tetrahydro-9-methoxy-6,12-imino-5H-benzo [5 ,6] cyclooct[ 1,2-b] indole A solution of 7.0 g. of 6,7,12,13-tetrahydro-9-methoxy- 14-benzyl-6,l2-imino 5H benzo[5,6]cyclooct[1,2-b]indole in 200 ml. of glacial acetic acid is hydrogenated at atmospheric pressure using 1.4 g. of 5% palladium on carbon as the catalyst. The catalyst is filtered off, and the filtrate is added to 700 ml. of ice-water. The solution is made basic with ammonium hydroxide and the resulting precipitate is collected. Trituration with methanol givesv 5.5 g. of 6,7,l2,13-tetrahydro-9-methoxy-6,12-imino-5H- benzo[5,6] cyclooct[1,2-b]indole, M.P. 289-291 dec. Recrystallization from methanol-dichloromethane gives material, M.P. 290-291 dec.

Analysis.For C H N O Calcd (percent): C, 78.59; H, 6.25; N, 9.65. Found (percent): C, 78.46; H, 6.13; N, 9.51.

EXAMPLE 4 OCHa N ALL 6,7,12,13-tetrahydro-9,lO-dimethoxy-14-methyl-6,l2- imino-SH-benzo [5 ,6] cyclooct[ 1,2-b] indole A mixture of 20.7 g. (0.045 mole) of 1-(indol-3-ylmethyl)-6,7-dimethoxyisoquinoline methiodide, 5.1 g. (0.135 mole) of lithium aluminum hydride, and 450 m1. of tetrahydrofuran is stirred for 18 hours at room temperature. The reaction mixture is hydrolyzed and filtered. To the filtrate is added 300 ml. of 1 N hydrochloric acid and the tetrahydrofuran is distilled oil. After the addition of 200 ml. of methanol and ml. more 1 N hydrochloric acid, the mixture is refluxed for 1 hour and the methanol is distilled off. The aqueous mixture is made basic with ammonium hydroxide and extracted with dichloromethane. The extract is triturated with methanol to give 12 g. of 6,7,12,13 tetrahydro 9,10 dimethoxy l4 methyl- 6,l2-imino-5H-benzo[5,6]cyclooct[1,2-b]indole as a crystalline product, M.P. 225-227. Recrystallization from methanol-dichloromethane gives 10.5 g. of material, M.P. 227-228.

Analysis.For C H N O. Calcd (percent): C, 75.42; H, 6.63; N, 8.38. Found (percent): C, 75.37; H, 6.75; N, 7.17.

The hydrochloride, recrystallized from ethanol-methyl ethyl ketone, has M.P. 234-240 dec.

Analysis-For C H N O -HCI. Calcd (percent): C, 68.01; H, 6.25; CI, 9.56; N, 7.55. Found (percent): C, 68.29; H, 6.37; Cl, 9.72; N, 7.61.

EXAMPLE 5 NOHs 6,7,12, 13 -tetrahydro-9-methoxy-5,14-dimethyl-6,12- imino-SH-benzo [5,6] cyclooct[ 1,2-b]indole To a solution of 5.2 g. (0.132 mole) of sodium amide in 1000 ml. of liquid ammonia is added a slurry of 20 g. (0.066 mole) of 6,7,12,13-tetrahydro-9-methoxy-14-methyl-6,12-imino-5H-benzo[5,6]cyclooct[1,2-b]indole in 500 ml. of tetrahydrofuran. The solution is stirred for 1 hour, 9.6 g. (0.068 mole) of methyl iodide is added, and stirring is continued for an additional hour. The ammonia is evaporated 01f, the tetrahydrofuran is removed using a rotary flash evaporator, and the residue is partitioned between dichloromethane and Water. The dried dichloromethane solution is evaporated to a gummy residue which is dissolved in 1000 ml. of ether and treated with ethereal hydrogen chloride. The resulting precipitate is triturated with Z-butanone and recrystallized from ethanol to give 15.8 g. of the crystalline hydrochloride of 6,7,12,13-tetrahydro 9 methoxy 5,14 dimethyl 6,12 imino 5H- benzo[5,6]cyclooct[1,2-b]indole, M.P. 264-265 dec. Recrystallization of a portion gives an analytical sample, M.P. 265.5-266.5.

Analysis.For C H N O-HCl. Calcd (percent): C, 71.08; H, 6.53; Cl, 9.99; N, 7.89. Found (percent): C, 70.99; H, 6.54; Cl, 10.13; N, 7.69.

Basification of an aqueous solution of the hydrochloride, extraction with dichloromethane, and evaporation of the solvent yields the amorphous base A filtered petroleum ether solution of the base is evaporated; the residue, after drying in vacuo at 80, melts at 85-90 and shows a single spot on thin layer chromatography.

Analysis.-For C H N O. Calcd (percent): C, 79.21; H, 6.96; N, 8.80. Found (percent): C, 78.95; H, 7.07; N, 8.61.

Refluxing an acetone solution of the base with methyl iodide results in precipitation of the methiodide, M.P. 306-307 dec.

Analysis-For C H IN O. Calcd (percent): C, 57.40; H, 5.47; N, 6.09. Found (percent): C, 57.47; H, 5.49; N, 6.27.

EXAMPLE 6 If \N OCH3 CHzCnHs 14-benzyl-6,7,12,13-tetrahydro-9-methoxy-5methyl-6, 12-imino-5H-benzo[5,6]cyclooct[l,2-b]indole OCHa 6,7,12,13-tetrahydro-9-methoxy-5-methyl-6,l2-imino- SH-benzo [5 ,6] cyclooct[ 1,2-b] indole A solution of 12.0 g. (0.03 mole) of 14-benzyl-6,7,12,- l3-tetrahydro-9-methoxy 5 methyl 6,12-imino-5H- benzo[5,6]cyclooct[l,2-b]indole in ml. of glacial acetic acid is hydrogenated at an initial pressure of 50 lb./ sq. inch gauge using 1.2 g. of 5% palladium on carbon as the catalyst. The catalyst is filtered off and the filtrate is added to 400 ml. of ice-Water. The solution is made basic with ammonium hydroxide and extracted with dichloromethane. Evaporation of the dried solution gives a residue which is triturated with ethanol to give 8.4 g. of the crystalline base, M.P. 142145. Recrystallization of a portion from ethanol gives an analytical sample, M.P. 146-147.

Analysis.F0r C H N O. Calcd (percent): C, 78.92; H, 6.62; N, 9.20. Found (percent): C, 79.21; H, 6.60; N, 9.25.

The hydrochloride, after being recrystallized from ethanoldichloromethane, has M.P. 286287 dec.

Analysis.-For c ,H N o-Hc1. Calcd (percent): C, 70.48; H, 6.21; CI, 10.40; N, 8.22. Found (percent): C, 70.25; H, 6.41; Cl, 10.43; N, 8.17.

We claim:

1. A compound of the formula:

wherein R is hydrogen, lower alkyl or phenyl lower alkyl; R is hydrogen, lower alkyl, or phenyl lower alkyl; R is hydrogen, or lower al-koxy; and R is hydrogen or lower alkoxy, and its non-toxic pharmaceutically acceptable acid addition salts.

2. The compound of claim 1 which is 6,7,12,13-tetrahydro 9 methoxy-14-methyl-6,l2-imino-5H benzo[5,6]- cyclooct[1,2-b]indole and its non-toxic pharmaceutically acceptable acid addition salts.

3. The compound of claim 1 which is 6,7,12,13-tetrahydro 9 methoxy-14-benzyl-6,IZ-imino-SH-benzo [5,6]- cyclooct[1,2-b]indole and its non-toxic phannaceutically acceptable acid addition salts.

4. The compound of claim 1 which is 6,7,12,13-tetrahydro- 9,10 dimethoxy l4-methyl-6,l2-imino-SH-benzo- [5,6]cyclooct[l,2-b]indole and its non-toxic pharmaceutically acceptable acid addition salts.

5. The compound of claim 1 which is 6,7,12,13-tetrahydro 9 methoxy 5,14-dimethyl-6,12-imino-5H-benzo- [5,6]cyclooct[1,2-b]indole and its non-toxic pharmaceutically acceptable acid addition salts.

6. The compound of claim 1 which is 14-benzy1-6,7,12, 13-tetrahydro 9 methoxy 5 methyl 6,12-imiuo-5H- benzo[5,6]cyclooct[l,2-b]indole and its non-toxic pharmaceutically acceptable acid addition salts.

7. The compound of claim 1 which is 6,7,12,13-tetrahydro 9 methoxy 5-methyl-6,1Z-imino-SH-benzo[5,6]- cyclooct[l,2-b]indole and its non-toxic pharmaceutically acceptable acid addition salts.

8., The compound of claim 1 which is 6,7,12,13-tetrahydro 9 methoxy 6,12 imino-5H-benzo[5,6]cyclooct- [l,2-b]indole and its non-toxic pharmaceutically acceptable acid addition salts.

9. Process for the production of a compound of the formula:

wherein R is hydrogen; R is lower alkyl of phenyl lower alkyl which comprises contacting a compound of the formula:

with an excess of a dilute aqueous mineral acid at a temperature of about 90 C. to 98 C.

No references cited.

DONALD G. DAUS, Primary Examiner 

